[show abstract][hide abstract] ABSTRACT: This is a multicenter prospective clinical study using a modified Knee Society scoring system which evaluated the effect of age, gender, weight, preoperative range of motion and knee score, previous surgery, and modification of the posterior femoral condyle geometry on postoperative range of motion. The primary outcome variable was change in flexion. The data were collected from 5 surgeons using a single total knee system. The current study has 621 patients enrolled, of which 282 total knee replacements have followup of 12 months and 86 have followup of 24 months. Multivariate analysis was used to evaluate the data. The variables listed were examined as to their relationship to changes in flexion. Patients were divided into 3 groups: preoperative flexion less than 90 degrees, 91 degrees to 105 degrees, and greater than 105 degrees. When comparing the patients with preoperative motion less than 90 degrees to those with motion greater than 105 degrees, the first group improved 26 degrees more than the latter. They also improved 12 degrees more than the midrange group. The midrange group improved 14 degrees more than the upper range group. These values are all adjusted to eliminate differences due to the other variables. None of the other variables showed a significant correlation with the flexion outcome. To analyze the knee score, the group was also divided into 3 groups: preoperative score less than 27, 28 to 40, and greater than 40. The preoperative knee score was the best predictor of the postoperative knee score. The patients with preoperative knee scores below 27 improved 16 points more than those in the 27 to 40 range and 33 points greater than the greater than 40 group. To analyze functional evaluation, the patients were divided into 3 groups based on preoperative score: less than 40, 41 to 50, and greater than 50. Those in the less than 40 group improved 14 points more than the midrange group and 35 points more than the greater than 50 group. Analysis of delta range of motion and delta pain showed similar results. Age, weight, previous open surgical procedure, and altered femoral component contour, did not seem significantly correlated with changes in postoperative flexion. The best predictors of postoperative clinical results are the preoperative scores.
Clinical Orthopaedics and Related Research 11/1996; · 2.79 Impact Factor
[show abstract][hide abstract] ABSTRACT: Postoperative knee flexion in patients undergoing Insall-Burstein-II total knee arthroplasty at 2 years was evaluated regarding two basic questions: what groups of patients gain or lose the most flexion and what groups of patients have the best or worst postoperative flexion. Thirteen preoperative variables (maximum flexion, flexion arc, tibiofemoral angle, quadriceps strength, extensor lag, Knee Society score, Knee Society patient assessment, gender, age, height, weight, diagnosis, and surgeon) and four postoperative variable (leg length change, tibiofemoral angle, distance from patella to the joint line, and the tibial prosthesis anteroposterior translation on a lateral radiograph) were used in an attempt to explain postoperative flexion. The analysis was performed on 164 consecutive Insall-Burstein-II total knees in which the data were gathered prospectively on a time oriented medical record database. A regression tree analysis was used to identify several groups of patients, characterized by preoperative factor values, who had markedly above average performance on postoperative flexion. The preoperative factors identified include preoperative flexion, flexion arc, tibiofemoral angle, extensor lag, diagnosis, and age. The only postoperative variable of significance was tibiofemoral angle. Among the potential determinants of postoperative flexion that failed to appear predictive were the Knee Society scores and surgeon. Preoperative flexion is known to be a critical determinant of postoperative flexion in total knee replacement. However, in the current study, preoperative flexion accounted for only half of the difference between the best (122 degrees) and the worst (88 degrees) group, as determined with regression tree analysis.
Clinical Orthopaedics and Related Research 09/1998; · 2.79 Impact Factor
[show abstract][hide abstract] ABSTRACT: Retrospective review of 1216 primary total knee arthroplasties (TKAs) to evaluate incidence and predictors of arthrofibrosis, defined as flexion less than 90 degrees 1 year post-TKA. Incidence of stiffness post-TKA was 3.7% (45/1216). A matched case-control study was then conducted to identify predictive factors for this outcome. Preoperative flexion and intraoperative flexion were predictive of ultimate postoperative flexion (P = .001 and P = .039, respectively). There was no correlation between postoperative stiffness and specific medical comorbidities, including diabetes. Preoperative and postoperative relative decreased patellar height and stiffness postoperative were significantly correlated (P = .001). Although stiffness post-TKA is multifactorial, careful attention to surgical exposure, restoring gap kinematics, minimizing surgical trauma to the patellar ligament/extensor mechanism, appropriate implant selection, and physiotherapy combined with a well-motivated patient may all serve to reduce the incidence of stiffness post-TKA.
The Journal of Arthroplasty 02/2006; 21(1):46-52. · 2.11 Impact Factor
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